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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad4dc8bf8ef03d001593d5da66ce8403aa09232fd1a3d67f16944d06e5265203' 
  AND token = 'vrveus91/lFdvgkEEBK2XL3EB7Qd5gj4Qy+KR2oV3u0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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