SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e431cb5638b7206497303887db82eae1a5233b0b28b2cec8cfaf72e1bd52a42a' 
  AND token = 'agjXI+T+XRFz8ZVj4tKoyVSLtcLJzB/m/dJfV0tmhJA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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