SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b114448f2d195064cbded4d7167c7649e11b52e6061ec6499600f714c757507' 
  AND token = 'n7cymWS2vYQ1SuMenEY2rNSYlGQvDKYRhW/AjC2Dnl4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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