SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b71993b16d9c1bc701829bf9d49e7413fce3279bb101d08e5fc34d6241d4bc69' 
  AND token = 'k+0hxaoKNcADWtp6HMYRuPtG46UqgeCRF+PEMc5h42I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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