SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e832301c313543f0716a1c2d61ce9d8943878a17fbbf31f3c625ddfad5b470c8' 
  AND token = 'ZIV4UMND/Fi3lJswdeqRzgMLoogG6kb0+iN652oZ8Ew=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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