SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'cdc91c95d290d7a6463a80d9e5a593011f0885a7a2b4314eb4f19f1f42f8c739' 
  AND token = 'LLAQ17giAGBPH6PJD6nye/pb1dqsjFTLV7pVaxHhKNE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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