SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eea2f931d3c0adc3303ae3803355512e026a8bfba6d6be512eadc857d7be87af' 
  AND token = 'LKyhW1ngygrlIkYkZXwlYerTLKMq9OeKGp5+l6Rj94c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}