SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e778b526af313be7cd0eac8f185fa69ab11555870ebe1a59823a42977ffcad6' 
  AND token = 't174qxmAVgQcV3purzToK3z3aBQfiulupAEhmvmT9Go=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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