SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a4fe91940560c939ff723d010aa0afb788c86f63f4861f2d403c474240bfd9e' 
  AND token = 'qMYia2TccExBANC4Mglus5kTTLynAsTDYMaAOdXePds=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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