SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4842c8ec5ea76230a1707ce262f1eb9f7e351ac766cfe530cc25e010edf2c38' 
  AND token = 'pmf/0pK6qfQWfYPcnJLNI30rlZZMBHP2dKP80bwVqY0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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