SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55a7738c2b0f9c430f6a236913aaa20e2cb8971e906333480d5035532f339398' 
  AND token = 'aD+2hVpcKiz7Fmo17oTHDNDWLUIse4+6VXreorPoFTA=' 
  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"
    }
  }
}