SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3489614170691e029548e7574ebc1194acc76372550e1b2ac749874528f0a33' 
  AND token = 'fcWb5/tqBMCLucdFOIb4suwJI/cTJXE2cAhHtbH2I5s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}