SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0df2dfe5fe053cfc27c0335db2a9e29fa6d021600469af2b6407397813f7db3d' 
  AND token = 't7Qqc3TBOsKA8q1GHNJLNebm14Xcs+eB3GKRMRXE88s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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