SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7221391081e63b716906aee51db2f2f0c2d4b7788ed08112e7569d06ca8bc3b5' 
  AND token = 'SdCW/5MgDMBaBkAta4YwUy2VMjz3+sDCLkFukwJA5Sc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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