SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d686901ab96605aac5d184cd0324dae9a5e3819a40966b9df2fa35ca8f50c12' 
  AND token = 'Ru+RzT8q442zvG9YXmM+z+hIsHFOBJ/MgAFJNaswzx8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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