SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '975d2ce88dc454fe5d94f10a25365636308cce5eb289b8750e3cf122eb6462de' 
  AND token = 'AOWBfUdePVQBiPazq8A+O1w+moNIRPZKqMRMo0vvf2U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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