SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88a9315a86e69f186b6d77a8852b06e8b819f0eb4d3331f47483ed9dcbd0782c' 
  AND token = 'MS+NM/yV75/soZRBr+TXTzhwvuNtI+whlnqECIVfQDs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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