SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52fc4ed096521811c6495f0a88719a0b4f06b0640917d8b64102aa53b1308062' 
  AND token = 'vvoDiOuJxuLVvliIIj0ENkpFrz74XJGyZ/fhukyRciU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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