SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9b68e26b7814670c7878801271fdbfdf7d907a8fa0a8548bc75fe7c8fa89957' 
  AND token = 'z4RLAxlIW7gRmcbgQ5qkKvbL4cAgVCDxhjJsT2FN3Dc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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