SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a572dc2f26c8a9145a1f681fa0fe3ee05df7bfdb44a31a0ddfc86783d519786d' 
  AND token = 'OfPp0W2XgunSUKh56QB2cjzArO2CPQJAAouWHiQHP3I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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