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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5cb0e2f74a4ba73636205dc45f1e4c1c83c5fa74ebecb76d1fcb7d99d435ae04' 
  AND token = 'cu5kXELpH89srS3GRhHUn+rTBZTqlqE9wVRa5x6GO6E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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