SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a9ce74875763480cceeb43ad0b95294a9615fe77343160d2e4df3d6742c791f' 
  AND token = 'UXLrglsqPc2u2p++vx90+JDgUYctsuLJ89Vx9dczYt8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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