SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '5a2a0dd3305352c37c4efe51925b99c4488b6e3dfcff48c28d138fee20a3b8ce' 
  AND token = 'YE7rf9/fAKmN7fPTlBRyMnxejCG0tHp9532QgznRtkU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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