SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3147c418028ca62f5ad3f8ebf712b9d8751931a71240a1f3f9620edf1ab3da4b' 
  AND token = 'dqMsIHhvuLBHmXEipq1UXgCOB5bDgKB7x4ggZ0lR8XI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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