SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5190836dbfb7713fd55adcd38f65ec1ecb1bbe41288e68fc01ce936884b0dd98' 
  AND token = 'JwPLHMbP351ocCYsFo8AOrMuGN1fmHroH8giY0pUB34=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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