SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e881938b3bcca6ecfbd2a836227ed58b448991377526eff951773cb94a42bf4' 
  AND token = 'Q1bA5+8CHDKPDRPpXY3ZzHm3joiOHJREEzYOaiJu0qs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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