SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87a51f6620f12e3a857e029ac61f69ca5142baae79534b60c9632f831721a394' 
  AND token = 'jaF9Y0Wf9N8HFSPjTa+IfaED5p9kwQVkJnux5wp08VE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}