SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cfdcc78211ef37ca6af12df28fe5231c97daa486d97f1df12ed7c4d1201939f3' 
  AND token = 'QNrgZyfTtCo+vqQom+pdKgDdCkK5BzOip/LvEy174dQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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