SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '480036b22706b03c65ec35991817392390714608417233035d9d2f1636b4da84' 
  AND token = 'OtIQJQyeGDGJk05NxkihorNZJfFCzvBjWsj0AOnCa3o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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