SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6399d72304aea8314cfe98562924fa64d54b9ddcfd9edf150b6c045a4d4589ce' 
  AND token = 'was/C9erdKdT7EEsWQnfideAP2ktZLaxPrgmOrMItno=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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