SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fce8cbf1a3dd08a9118c041ecb78d4983c2f8f7acc7d965023c660f44aaf9052' 
  AND token = 'z2DIrgbAqZCNv3QNDGeA2XzsVJkFXpQC7tlDtbDfeJU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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