SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f489252d26c9c5c447bcd695b902b33d64847905040b6372b84bdea648ecbac' 
  AND token = 'J3RGRTF+DqbNv9OiXYwGSie0OMzjGKBlPtVdfXdgBoU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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