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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38f6d640d66b688237a01399444697862e31d9fa2b40adbf04e75693ac033c1e' 
  AND token = 'lw/2nkqSq541+oZ7SeKEBPUb+rQBRP8zE0cX4XKad+k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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