SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90a7f4af718de9d201513dbeca1fbf8e7843aa7ae0b7b55020622d9ef065dcc4' 
  AND token = 'tHFYbE7DJQstEHbyO3ZUboKlmzNwNHR8eLYpfvHr0G4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}