SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3f73200c41440af6e18175304ba5585d2117ce75250b1f4c4d98844c6ccbd24' 
  AND token = 'Idy5mtIDKYxRFZTVIYjxuVEKsOz4VUf3SmjZsDbM5cM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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